/**
 * Created with IntelliJ IDEA
 * Description:
 * User: Administrator
 * Data: 2023 - 07 - 17
 * Time: 14:05
 */
class Solution4 {
    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
        if(root == null) return false;//在这里subRoot一定不为null
        if(isSameTree(root, subRoot)) {
            return true;
        }
        if(isSubtree(root.left, subRoot)) {
            return true;
        }
        if(isSubtree(root.right, subRoot)) {
            return true;
        }
        return false;
    }
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p == null && q == null) {
            return true;
        }
        if((p != null && q == null) || (p == null && q != null)) {
            return false;
        }
        if(p.val != q.val) {
            return false;
        }
        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    }
}